If you feel in the dark when it comes to "cloud computing", you're not alone. In a nutshell, "cloud" is a metaphor for the Internet so it basically refers to applications offered and stored on the web.
Files and office related software that used to only be available through your computer can now be easily stored online instead of taking up space on your hard drive.
Furthermore, as we become more mobile through devices such as tablets and smartphones, it's important that information be accessible no matter where we are or what device we're on. The cloud in essence follows you wherever you go.
People are moving to the cloud for many reasons but as with anything, there are pros and cons. Security, privacy and Internet downtime are the major concerns but as time goes on, there's no doubt that cloud computing will continue to grow in popularity. Hopefully this has shed some light on a cloud of confusion.